Machine gun



l. R. BARR MACHINE GUN Dec. 29, 1959' 2 Sheets-Sheet 1 Filed Feb. 16, 1955 INVENToR.

mwm R. BARR BY @MM IIA ATTORNEY 2 Sheets-Shee 2 l. R. BARR MACHINE GUN Dec. 29, 1959 Filed Feb. 1e, 1955l v .om

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United States Patent O MACHINE GUN Application February 16, 1955, Serial No. 488,451

` 13 Claims. (Cl. 89-125) This invention relates to machine guns, and more particularly to a machine gun` having a high rate of tire coupled with a light andcompact configuration.

For certain military purposes, particularly in high speed combat aircraft, it is important to provide machine guns having an extremely high rate of lire. It is alsoessential that such guns be light and compact because of the limitations imposed on these factors by the design characteristics of combat aircraft. The conventional guns presently in use utilize a reciprocating bolt moving axially with respect to the bore of the gun to extract the empty cartridge case from the gun chamber on the aft stroke and to push a new cartridge into the chamber on the forward stroke. This reciprocating action of the bolt establishes the rate of re 'for the gun. Obviously, the stroke of such a bolt must be slightly longer than the cartridge in order to allow ejection and insertion of a new cartridge in the chamber. Since the stroke of the bolt is fixed by the length of the ammunition used, any increase in the rate of re must be accomplished by increasing the velocity of the bolt. v This, in turn, results in increased accelerations in the bolt and the other moving parts of the gun mechanism, so that the maximum rate of re is determined by the maximum permissible accelerations in the moving parts'.

The present invention overcomes this limitation by providing a sliding breech block arrangement and a short stroke rammer for loading the cartridge into the chamber. Utilization of a sliding breech block allows the use of the residual gas pressure in the barrel toy blow the spent case from the chamber, thus eliminating the need for an extractor. Because ofthe short distances which the breech block and the rammer are required to move, an extremely high rate of fire may be obtained without increasing the velocities of the moving parts above the permissible limits. It is the object of this invention therefore, toprovide a machine gun having a high rate of re.

In the drawing: f Figure 1 is a sectional View of a gun constructedl in accordance with this invention showing a round in the chamber of the gun with the breech block closed for tiring.- Figu're 2 is a sectional View showing the breech yblock open and an empty cartridge case striking the deflector plate after having been expelled from the chamber by residual gas pressure remaining in the barrel of the gun after firing. i

Figure 3 is a sectional View showing a new round l `traveling forward into the chamber after having been accelerated by the rammer and being guided by the cartridge guide which has moved the round into alignment with the bore of the gun. l

Figure 4 is a sectional view showing the new round in 2,918,847 Patented Dec. 2s, .1959,

plated by this invention comprises a gun barrel 'licarrie'd in a conventional manner by a barrel support 2. A gas. cylinder 3, which may be formed integrally with the barrel support 2, as shown in the drawing, connects with the bore 4 of the gun by means of a port 5. A piston 6 carried by the forward end of a slide 7 is contained Within the'cylinder 3. The rear end of the slide 7 is supported by a pair of slide tracks 8 which engage projections 21 which are formed integrally with the slide.

Breech block 9, which is disposedV at the rear-end of the barrel 1, is free to slide vertically in guide block 1.4 from the closed position depicted in Figure 1 to the open'posi-A tion shown in Figure 2. n n

A pair of upstanding arms 11 carried bythe breech block have cam surfaces 12. formed at the upperendof each arm which are engaged by the inclined surfaces 13 on the slide 7 to lift the breech block 9 upon rearward motion of the slide. A pair of compressionsprings 45, best vseen in Figure 5, act against'lugs 15 carried bythe breech block 9 to urge the block into its closedrposition between guide block 16 and the rear end of the cartridge case 17 as shown in Figure l. A cartridgestop 3 9 is carried at the rear of chamber 40 to act as a buffer and limitV the forward motion of the cartridge. The stop 39 encircles the rear of the chamber 40 and is urged toward its rear position, as shown in Figure 2, by springs 41..A

A rocking cartridge guide 18 is pivoted on pin 19 for motion between an inclined position as in Figure l and an aligned position with respect to the gun barrel las shown in Figure 3. Deector plate 20 is urged against the bottom of guide 18 by spring 22 which acts to maintain the guide and the deector plate in the upwardly tilted posi,- tion shown inFigure l. A tipper 23 is pivoted on ,pin` 24 and carries a follower 25 which is engaged in cam slot 26 formed in slide 7 so that reciprocating motion of the slide will rock the tipper between upper and lower positions.y

A rammer 27 axially aligned with the bore 4 of the gun barrel 1 is carried for sliding motion on guide pin28 which is fixed to the gun housing 29. One end of a rocking lever 30, which is pivoted on pin 31, engages. a slot 32 formed in the rammer 27, the other end of the leverextending into an elongated slot 33 formed in the underside of slide 7. Pin 31 is carried in yoke arm 43, which is r'eciprocable within tube 49 against the action of spring 50. Beginning with a round in the chamber, the gunis fired by actuating the firing pin 34 carried within the breech block 9. Since the mechanism for actuating the tiring pin is conventional and forms no part of the invention, it has Y been omitted from the drawing for clarity in presentation.

As the projectile 35 moves past the gas port 5 in thegun barrel 1, a portion of the propelling gases enters the cylinder 3 and accelerates the piston 6 and slide 7 rearwardly. A shoulder 36 which is carried on the pistonrod 10 forward of piston 6 closes the port 5 shortly after the slidev to'be deliected downwardly and out of the gunby the.

deflector plate 2i) which is in its upwardly tilted position. When released by the ejected cartridge case the cartridge stop 39, which has been held in its forward position by shoulder 42 on the cartridge, will be moved rearwardlyby the action of springs so that projection 4401i the stop engages the underside of the breech block, locking it in the up position. Immediately thereafter, the continuedreat-, ward motion of the slide causes the cam slot 26 to force` the tipper 23 downward toward its lowerrnost position.

Simultaneously, the forward end 37 of ythe slot 33 inthe 3 underside of slide 7 strikes 27 forward to' accelerate anew roundstoward ythe barrel 1. As the round coasts forward cam slot 26 continues f to move. the `tipper downward runtil `the round is laxially aligned with the vbore 4 at which time the round is just entering 'the chamber. "The arrangement of piston 6 and piston rod 1t) is such that practically all thefenergy of the gases 'trapped behind the lever 30, driving rammer thepistonin gas cylinder 3 when shoulder 36 closes port i ,Sis extracted yin driving slide 7l toward its rearward position (Figure 3) sothatslide 7 is powered throughout its entire stroke. After slide 7 has lifted breech block'9 and the residual gases have extracted. spent round 17, slide 7 is been shown and described, it Iis revident rthat'many r:

changes and modifications maybe made without depart* ing from the spirit of the invention or the scope of the appended claims. v f f f I claim: f

'1. yA machine guncomprising a barrel, slide meansref sponsive to gas pressure within said barrelto be recipro.

' cated with' rrespect thereto, rclosure means reciprocable in the, position shown inv Figure 2,r with ytipper 23 about f to act on thefresh round.` Before this position of'slide 7 isreached, port has been yclosed by shoulder 36 and the gases having entered in gas cylinder 3 are trapped therein because rod 16 is still closing the exhaust port. As' the v slide moves from the rposition shown in Figure 2 to the positionfshown'in'Figure 3, itis ystill under the iniiuence lothe gas trapped in the cylinder so that both tipper and springS are effectively actuated to perform their, functions. After thisfpositiveactuation of tipper 23, rod is f withdrawn fromthe exhaust port (Figure 3) andthe f' trappedV gases arevented to atmosphere, so that spring 50 which had previouslyfbeen compressed can yreturn slide transversely ywith respect toy said barrel for closingy the breech thereof, said` closure means beingv responsivev tor motion of said slide to open said breech, pivoted means 'supported' behind` said'barrel and responsive to recipro-y cating motion of said slide to be pivotedbetween vanfin-y clinedy position intersectingthe axis of said barrel and a yposition yaxially raligning a cartridge ywith the bore rof 7to its rst position.` Thus the gases generated'upon firingy f f a round are'eticiently' utilized tol positively actuate component parts in the system.

As cartridge guide 18 reaches its lowermost position, the rammer 27 reachesA the limit of itsy forward travel,

vpreventing further rotation oflever 30, so that spring 50 is compressed and then reacts to accelerate slide' 7 vforf wardlyto continuefthe .cycle. If desired, additional means maybe included to accelerate the slide 7 during its forward stroke, the use of a portion ofthe propelling gases' from "the gun* barrel being suitable for this purpose.

yAsthe slide7- approachesvthe forward limit of its travel,

therear` end 51 of the slot 33 strikes lever y30, returning the rammer 27 to its rearmost position in readiness to facceleratefthef nexty round as the action of the gun con-l ,tinues The breech block 9, at this point, is held open by theprojection 44 on the cartridge stop 39 as in Figure 3. Thus, cartridge stop 39 serves as a releasable latch for breech block 9.

"-Meanwhile, the velocity imparted by the rammer 27 to round 38 carries the round home into the chamber 40, `so that shoulder 42 on the cartridge case engages stop 39, compressing 'springs 41 and releasing breech block `9, which is slid downward by action of springs 45 into position behind the round so that the cycle is ready to be repeated.

`-The feed mechanism used to advance subsequent rounds into` position in-the cartridge guide as the gun is fired `1s of aA conventional type and is consequentlyomitted from the drawing for clarity.A

By eliminating the conventional reciprocating bolt in the above described manner, the ramming stroke can be begunw almost as soon as the breech block has travelled the short distance necessary to` open the breech of the gun, since the spent cartridge case is expelled from the barrel'. at` arhigh velocity as soon as it is released by the breech block. Thus a substantial portion of the time interval required for a conventional reciprocating bolt to be retractedfrom the breech is saved and the ring rateof the gun can be markedly increased.

The arrangement described provides a simple and reliable system for reducing. the time required to openthe breech,` remove the spent cartridge case, insert a new round, andilock the breech before ring.` ItA eliminates thesneed for an extractor `by allowing the spent case to beblown free of the chamber by the residual gas pressure in the` gun barrel, and by a unique arrangement of a swinging cartridge guideA and` spent case deector., al,

said" barrel, the side of said pivoted means ipresentedito f ward `said breech when in said inclined position acting to f 'dellectf ay cartridge casev when ejected yfrom said breech, f raniming means responsive to rearward motion of ysald slide toy impart yan. initialvelocity to said cartridge suii-` ycient to impelsaid cartridge into sad breech, the other f side of said pivoted means formingv a guidev for ysaid v cartridgel duringl its motion into said breech, latch means rfor latching said closure means in open position, l f f l said` latch means being engagealilev by ysaid cartridgev ,f during entry rof saidcaritridgeint'o said breech to unlatch said closure means. f

2. A machine gun comprising a barreL'slide means re f sponsive to lgas lpressure within said barrel to be reciprovcated with ,respect thereto, closure means reciprocabley f transversely with respect vto said barrel having meansy ycooperable ywith and responsive to motion of said slide to openfthe breech of said barrel, yresilient means for`urg f ing `said closure means into'closedy position,releasabley f latch means yfor latching said closure means in open position, ypivoted means supported behind said lbarrel ,hav-F..

ing means cooperable withy andv responsive yto reciprocating motion of said slide to be pivoted between an inclined position intersecting the axis of said barrel and ya position axially aligning a cartridge with the bore of said barrel, the side of said pivoted means presented toward said breech when in said inclined position acting to deect a cartridge case when ejected from said breech, and ramming means having means responsive to motion of said slide to impart a velocity to said cartridge suflicient to impe] said cartridge into said breech, the other side of said pivoted means forming a guide for said cartridge. during' its motion `into said breech, said latch means having means responsive to movement of said cartridge into said breech to unlatch said closure means and allow said closure means to be moved into closed position by said resilient means.

3`. An automatic firearm comprising a barrel and a slide member longitudinally reciprocable upon ring, a breech block transversely' reciprocable with respect to said barrel for opening and closing the breech thereof, means responsive to rearwardA motion of said slide member for opening said breech while the gas pressure within said barrel due to tiring is suicient to eject the spent cartridge case from said breech, `spring means acting to urge said breech block' into closed position, releasable latch means effective when said breech is empty to latch said breech block in open position, means responsive to insertion of a cartridge into said breech for disabling said latch means whereby said spring means is. effective to close said` breech, cartridge guide means pivotally carriedf behind said breech for movement between an in clinedposition intersecting the axis of said barrel and. a position aligning said cartridge in said guide with said breech, rammingV means' responsive to rearward motion of said slide member to impart a` forward velocity to said cartridge in said guide sucient to carry said cartridge 5. into said breech, and means responsive to reciprocating motion of said slide member for moving said cartridge lguide means between -said inclined position during ejection of said spent cartridge case to said position aligning said cartridge in said guide with said breech as said cartridge is impelled forward by said ramming means.

4. A machine gun comprising a barrel, a slide longitudinally reciprocable upon ring said gun, a transversely reciprocable breech block, spring means acting to close said breech block, cooperating cam surfaces carried by said slide and said breech block respectively, said cam surfaces being engageable upon rearward motion of said slide to open said breech block, latch means carried by said barrel for motion between latching and unlatched positions, spring means normally urging said latch means into latching position so that said latch means may latch said breech block in open position, said latch means being engageable by a cartridge inserted into the breech of said gun to be moved out of engagement with said breech block, cartridge case dellecting means responsive to reciprocation of said `slide to be interposed behind said breech each time said breech is opened by rearward motion orf said slide, to deilect a cartridge case ejected from said breech, cartridge guide means also responsive to reciprocating motion of said slide to be moved between an `inclined position to receive a new cartridge and a position aligning said new cartridge with the bore of said barrel, `and ramming means disposed behind said guide means and responsive to rearward motion of said slide to impart a forward velocity to said new cartridge sufficient to propel said new cartridge into said breech, whereby said new cartridge engages said latch means to unlatch said breech block and allow said breech block to be moved into closed position by action of the first said spring means.

5. A machine gun comprising a barrel, a slide longitudinally reciprocable upon tiring said gun, a transversely reciprocable breech block, spring means acting to close said breech block, cooperating cam surfaces carried by said slide `and said breech block respectively, said cam surfaces being engageable upon rearward motion of said slide to open said breech block, latch means carried by said barrel lfor motion between latching and unlatched positions, spring means normally urging said latch means into latching position so that said latch means may latch said breech block in open position, said latch means being engageable by a cartridge inserted into the breech off said gun to be moved out of engagement with said breech block, cartridge guide means pivoted for motion between an inclined position to receive a new cartridge and a position aligning said new cartridge with the bore of said barrel, cartridge case deflecting means pivoted for swinging motion between a rst position and an inclined position behind said breech to deflect a cartridge case ejected from said breech, spring means acting to urge said deecting means into said inclined position and against the underside of said Iguide means, means responsive to reciprocating motion of said slide to move said guide means between said inclined position and said position -aligning said new cartridge with the said bore, and ramming means disposed behind said guide means and responsive to rearward motion of said slide to impart a forward velocity to said new cartridge sufficient to propel said new cartridge into said breech, whereby said new cartridge engages said latch means to unlatch said breech block and allow said breech block to be moved into closed position by action of the first said spring means.

6. A machine gun comprising a barrel, a breech block reciprocable transversely with respect to said barrel to open and close the breech thereof, resilient means urging said breech block into closed position, and latch means for latching said breech block in open position comprising a member mounted at the rear of said breech for axial movement with respect thereto, resilient means urging said member rearwardly, means formed on said member for engaging saidV breech'block to latch it into'A open position, and means forming an opening in said member axially aligned with said breech, the edge of said opening being engageable by the base of a round of ammunition inserted into said breech to move said mem`` ber forwardly to unlatch said breech block.

7. In a device of the type described, a barrel having a breech, a breech block mounted for transverse movement from a rst position blocking said breech to'a second position unblocking said breech, spring means biasing said breech block to said rst position, means on said barrel responsive to firing a round in the breech for causing said transverse movement, a latch on said barrel, means on said latch engageable with said breech block when in said second position to releasably retain the same thereat, and additional means on said latch adapted to be engaged by a fresh round upon its insertion into said breech to disable said iirst named means whereby said spring means causes said breech block-to move to said first position. f

8. In a device of the type described, -a barrel having a breech, a breech block mounted for transverse movement from a rst position blocking said breech to a second position unblocking said breech, spring means biasing said breech block toward said first position, movable actuating means responsive to ring a round in the breech for causing said transverse movement, means to releasably retain said breech block in second position while the expandable gases generated upon ring extract the spent round and until -a fresh round is inserted therein, and deecting means positioned behind and in alignment with said breech for deflecting said spent casing upon extraction of the same.

9. The device of claim 8 provided with loading means compri-sing means responsive to said actuating means for moving said deflecting means out of alignment after said spend round is deected, and ram means actuated by said actuating means for inserting a fresh round into said breech.

10. The device of claim 8 having said deecting means movably mounted, means associated therewith to hold said fresh round, means made effective by movement of said actuating means for moving said deecting means out of alignment, and ram means responsive to further movement of said actuating means for moving said fresh round from said associated means and loading it into said breech.

1l. The combination, with a machine gun having a barrel with an axially extending bore and a breech at one end, of a breech block, means mounting said breech block on said breech for movement from a first position to retain a cartridge therein during firing to a second position to eifect movement of a cartridge in said breech, an actuator displaceable relative to said barrel, means on said actuator responsive to firing a cartridge for causing a rearward displacement of said actuator, means 0n said actuator cooperable with said breech block during initial rearward displacement for moving said breech block to said second position so that residual gas pressure within said bore will extract the cartridge, supporting and deflecting means adapted to support a fresh cartridge and normally positioned in the path of the extracted cartridge for dellecting the same, means mounting Said supporting and delecting means for movement from its normal position to a position aligned with said bore so as to provide a guide for insertion of a fresh cartridge into said breech, means responsive to linal rearward displacement of said actuator for simultaneously effecting movement of said supporting and deecting means from its normal position and imparting an acceleration to said fresh cartridge to insert the same in said breech, means for causing forward displacement of said actuator, and means for causing movement of said breech block to its irst position.

12. A machine gun for tiring a succession of cartridges 7 comprising a barrel having a breech into which a cartridge is irisertable, a slide reciprocably mounted on said barrehmeans responsive to gas pressure generated within the bore of the barrel when the cartridge is tired for causing rearward movement of said slide, a breech block movable from a rst position closing the breech for preventing rearward movement of the cartridge as it is red to a second position opening the breech for etecting movement of the cartridge after it is tired, means responsive to initial rearward movement of said slide for moving said breech block to the second position before the gas pressure within the bore is dissipated whereby such gas pressure ejects the cartridge in a rearwardly directed path, guide means mounted rearwardly of said breech for Isupporting a fresh cartridge and movable from a normal position at which the fresh cartridge is inclined with respect to the axis of said bore to a loading position at which the fresh cartridge is aligned with respect to the axis of said bore, and means responsive to nal rearward movement of said slide for simultaneously imparting a forward acceleration to the fresh cartridge and moving said guide means to the loading position so that the fresh round is aligned with the axis of said bore when it enters the breech.

13. The machine gun of claim 12 wherein said guide means, when in its normal position, -is in the path of the ejected cartridge and serves to deflect the same.

References Cited in the le of this patent UNITED STATES PATENTS 

